The associated action calls SetGroupIndex when its GroupIndex property changes so that the action link can propagate the new GroupIndex value to the client object.

Value specifies the new value of the GroupIndex property.

As implemented in TActionLink, SetGroupIndex does nothing. It is not strictly necessary for descendant classes to override SetGroupIndex to set the client property that corresponds to the action's GroupIndex property, because the action itself implements the GroupIndex feature. That is, when an action's Checked property is set to true, it unchecks other actions in the same action list if they have the same GroupIndex value.